Now you can use Hijri datepicker for selecting date in Hijri. Normal AlmightyCS datepicker is also avilable with hijri date picker. you can select date from any of the picker and it will be converted vise-versa.
Specifications for "
Odoo Web (Hijri)Islamic Datepicker. The Hijri(Islamic) calendar is the official calendar in countries around the Gulf, especially Saudi Arabia.